CAN bus communication

What does 34 mean?

A message sent over the CAN bus was not acknowledged by another device on the network. This typically points to a communication issue, such as an incorrectly configured device, a disconnected bus, or a fault in the CAN network's physical layer. Loss of communication can prevent proper control and monitoring of the drive.

• Missing or incorrect termination resistors (e.g., 120 Ohm) at both ends of the CAN bus network.
• Break or short circuit in the CAN bus cabling (CAN_H, CAN_L, CAN_GND) causing signal degradation or loss.
• Incorrect CAN bus speed (baud rate) or node ID (address) configured on one or more devices (e.g., P3-10 "CAN baud rate", P3-11 "CAN node ID").
• Power supply issue to one of the CAN bus devices, preventing it from communicating.
• Defective CAN bus transceiver chip on one of the connected devices or the drive itself.

Click steps to track your progress.

1. 1

   Verify the presence and correct value (e.g., 120 Ohm) of termination resistors at both physical ends of the CAN bus network using an ohmmeter.

2. 2

   Check continuity and shielding of the CAN bus cable (CAN_H, CAN_L, CAN_GND) for breaks, shorts, or loose connections at each device.

3. 3

   Confirm that all devices on the CAN bus have unique node IDs (e.g., P3-11) and are configured for the identical baud rate (e.g., P3-10).

4. 4

   Measure the voltage levels on CAN_H and CAN_L lines (relative to CAN_GND) using an oscilloscope to check signal integrity and common mode voltage.

5. 5

   Temporarily disconnect devices one by one to isolate a potential faulty device or reconfigure the network with fewer devices to identify the source of the communication issue.